ath79: add support for Enterasys WS-AP3705i

ath79: add support for Enterasys WS-AP3705i

Hardware
--------
SoC:    Atheros AR9344
RAM:    128M DDR2
FLASH:  2x Macronix MX25L12845EM
        2x 16MiB SPI-NOR
WLAN2:  Atheros AR9344 2x2 2T2R
WLAN5:  Atheros AR9580 2x2 2T2R
SERIAL: Cisco-RJ45 on the back (115200 8n1)

Installation
------------

The U-Boot CLI is password protected (using the same credentials as the
OS). Default is admin/new2day.

1. Download the OpenWrt initramfs-image. Place it into a TFTP server
   root directory and rename it to 1401A8C0.img. Configure the TFTP
   server to listen at 192.168.1.66/24.

2. Connect the TFTP server to the access point.

3. Connect to the serial console of the access point. Attach power and
   interrupt the boot procedure when prompted (bootdelay is 1 second).

4. Configure the U-Boot environment for booting OpenWrt from Ram and
   flash:

   $ setenv boot_openwrt 'setenv bootargs; bootm 0xbf230000'
   $ setenv ramboot_openwrt 'setenv serverip 192.168.1.66;
     tftpboot 0x85000000; bootm'
   $ setenv bootcmd 'run boot_openwrt'
   $ saveenv

5. Load OpenWrt into memory:

   $ run ramboot_openwrt

   Wait for the image to boot.

6. Transfer the OpenWrt sysupgrade image to the device. Write the image
   to flash using sysupgrade:

   $ sysupgrade -n /path/to/openwrt-sysuograde.bin

Signed-off-by: David Bauer <mail@david-bauer.net>